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Aim The ecological niche of a species is dynamic at a variety of spatial and temporal scales; embracing this complexity is required for accurate assessment of species' niche requirements and to forecast how species will respond to novel and dynamic climates. In the context of recent advances in species distribution modelling, however, both the environment and the ecological niche of a species have often been treated and quantified as static entities. Here, our aim was to explore how species' realized niches and geographical ranges are dynamically shaped by the decoupled spatio-temporal availability of different environmental conditions, using the migration of Sylvia warblers as an example. Location Palaearctic, Afrotropical and Indo-Malay ecozones. Methods We used a species distribution modelling approach to evaluate the niche characteristics of Sylvia warblers under their actual migration strategies as well as null models assuming resident behaviour. We focused on climate and land cover as niche dimensions, taking into account the spatial availability of environmental conditions during the peak breeding and non-breeding season for each Sylvia species. Results Migration did not increase the overlap between breeding and non-breeding niches compared with breeding and non-breeding niche overlap in resident null models. Sylvia warblers did not compensate for the costs of a longer migratory journey by tracking their climatic niche or land-cover niche more closely. Instead, Sylvia warblers migrated further than the closest available area with suitable climate and land cover. Main conclusions Climatic niche tracking is unlikely to be the main driver of migration in Sylvia warblers. We suggest that taking dynamic environments into account and comparing actual niche characteristics to those resulting from alternative possible range dynamics enhances our understanding of the drivers behind organisms' movements and distributions. [ABSTRACT FROM AUTHOR]

Aim  To explore the potential impacts of climatic change on species with different migratory strategies using Sylvia warblers breeding in Europe as a ‘model’ species group. Location  Europe and Africa. Methods  Climate response surfaces and generalized additive models (GAMs) were used to model relationships between species recorded breeding and non-breeding ranges and recent climate. Species potential future breeding and non-breeding ranges were simulated for three scenarios of late 21st-century climate. The simulated potential future and present ranges were compared in terms of their relative extent and overlap, as well as their location. The impact of any shifts in potential range location on migration distance were quantified. Results  Potential breeding ranges consistently showed a shift northwards, whereas potential non-breeding ranges showed no consistent directional shift, even when trans-Saharan migrants were considered separately from resident/short-distance or partial migrants. Future potential range extent relative to simulated recent range extent varied considerably among species, although on average range extent increased. Overlap between future and recent simulated range was generally low, averaging < 36% for both breeding and non-breeding ranges. Overlap was consistently less for range-restricted than for widespread species. Migration distance increased generally, by about twice as much in the case of trans-Saharan migrant species than for short-distance migrants. In many cases potential future non-breeding areas were simulated in regions far from the species present non-breeding area, suggesting that new migration strategies and routes may need to be developed in response to climatic change. Main conclusions  Migratory species can be expected to suffer greater negative impacts from climatic change than species that are resident or undertake only short-distance or partial migrations. Trans-Saharan migrants face the greatest potential increases in migration distances, whereas range-restricted species are expected to experience major population reductions because of the limited, or in some cases lack of, overlap between their present and potential future ranges. [ABSTRACT FROM AUTHOR]